#include "apue.h"
#include <ctype.h>

int main(void)
{
    int c;
    while ((c = getchar()) != EOF)
    {
        if (isupper(c)) c = tolower(c);
        if (putchar(c) == EOF) err_sys("output error");
        if (c == '\n') fflush(stdout);
    }
    return 0;
}